Wire harnesses mounted on board of vehicles, such as hybrid cars and electric cars, have been conventionally known in which electric wires having different flexibilities, such as single-core wires and stranded wires, are connected to one another. For example, JP 2016-58137A describes a wire harness in which single-core wires are connected to stranded wires such that, when mounted in a vehicle, the single-core wires are used in the regions where no flexibility is required and the stranded wires are used in the regions where flexibility is required for connection with pieces of equipment. The conductor exposed at a terminal portion of each single-core wire by stripping the insulating coating therefrom is placed on the conductor exposed at a terminal portion of a stranded wire by stripping the insulating coating therefrom in a direction transverse direction to the direction in which both wires extend, and the single-core wire and the stranded wire are connected by ultrasonic welding. A shrinkable tube is fitted on or covers the connecting portion to ensure electrical insulation.
JP 2016-58137A is an example of related art.